1. Field of the Invention
The invention in general relates to transducers, and more particularly, a beam shaping technique using an acoustic baffle.
2. Description of the Prior Art
Sonar beam patterns are determined by the shape of the active face of the active transducer elements used to project or receive the acoustic energy. Obtaining a specific beam pattern from a standard shape element requires a design of complex arrays, use of amplitude and/or phase shading, or use of reflectors or baffles.
U.S. Pat. No. 3,949,348 assigned to the same assignee as the present invention and herein incorporated by reference, describes sonar apparatus wherein the sonar beam is modified from its normal shape by the use of an acoustic absorbing material having an acoustic impedance substantially equal to that of the surrounding water medium. It has been found that such apparatus, described in the patent, under certain operating circumstances, did not provide enough of a beam pattern modification and additionally, undesirable pattern ripples showed up.
The present invention describes apparatus similar to that described in the patent; however, the objectionable features that occurred for the particular operation involved, have been eliminated.